Femtosecond-resolved multiphoton ionization of C60 using X-ray pump X-ray probe with the LCLS FEL

We studied the time-resolved ionization of C$_{\mathrm{60}}$ using X-ray pump X-ray probe with 640 eV photons to examine the role of chemical effects, such as chemical bonds and charge transfer, on the fragmentation following multiple ionization of the molecule. The advanced simulations revealed that despite substantial ionization induced by the ultrashort (20 fs) X-ray pump pulse, the fragmentation of C$_{\mathrm{60}}$ is considerably delayed. This work uncovered the persistence of the molecular structure of C$_{\mathrm{60}}$, which hinders fragmentation over a timescale of hundreds of femtoseconds. Furthermore, we demonstrate that a substantial fraction of the ejected fragments are neutral carbon atoms.